1. Field of the Invention
The present invention relates to a rotational balancing structure for an A. C. (alternating current) motor to provide an improved rotational balance while the A.C. motor is operating.
2. Description of the Related Art
Applicant U.S. patent application Ser. No. 09/327,188 filed on Jun. 7,1999 and entitled RUSHLESS D.C. MOTOR ASSEMBLY discloses a brushless D.C. motor assembly comprising a balancing sheet made of material with magnetic conductivity. The balancing sheet and a stator are coupled by an axle seat, and a shaft of a rotor is rotatably mounted in the axle seat, thereby allowing mutual attraction between a permanent magnet on the rotor and the balancing sheet. Thus, the rotor has an improved rotational balance when it rotates.
An object of the present invention is to provide a rotational balancing structure for an A.C. motor that provides an improved rotational balance and reduces noise during rotation. A rotational balancing structure for an A.C. motor comprises a casing having an axle seat for rotatably holding a shaft of a rotor. A balancing sheet and a stator are mounted in the casing. The stator comprises plural stacked silicon steel plate wound around by a winding. An insulating ring is mounted to an end of the stator. Each of the stator and the insulating ring has a central hole. The rotor comprises an induction ring that is received in the central hole of the stator with an end face of the induction ring extending through the central hole of the stator for mutual attraction with the balancing sheet fixed on the casing.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.